Quality Management of Wire Harness Assembly

Due to work reasons, I often communicate with the quality manager of the wiring harness, and the most common complaints I hear are: the work is difficult to do, the personnel are difficult to manage, and the quality is difficult to control. Externally there are complaints from customers, internally there are various pressures on production capacity and equipment, internal and external troubles, and quality managers are often extremely busy.
The key to solving the problem of “busy” quality of wire harness lies in “prevention”. Complaints from external customers often stem from poor internal quality control. To achieve good quality, we must prevent on-site problems, nip problems in the bud, and nip them in the bud.
How to “prevent”?
Three inspections are carried out in the pre-process: first inspection, patrol inspection and final inspection.
Characteristics of the pre-process: high degree of automation, key positions, relatively stable quality, but once problems occur, batch production may occur, and the RPN value is high. In addition to regular TPM inspections of equipment every working day, employees also need to do “three inspections” during the production process.

Crimp size and tension measurement of wire harness terminals

In the terminal crimping operation, the front and rear height and width dimensions and the pulling force value are the key control items. The corresponding values must be recorded for the first and last inspections and patrol inspections of each shift. First inspection, inspection before starting the shift. Mass production can only be carried out after the first piece of crimping is qualified. Otherwise, the equipment needs to be debugged until it is qualified. Inspection is an indispensable part. Inspection is usually carried out by inspectors from the QC department. The purpose of inspection is to ensure the stability of terminal crimping and reduce quality risks. Final inspection is an easily overlooked link. Employees are often busy leaving get off work or switching materials, neglecting the final inspection. The purpose of final piece inspection is to change and record the number of crimping batches to facilitate future batch traceability.
Do three things well in the post-processing process: do not accept, do not manufacture, and do not pass on defective wire harnesses
Post-process characteristics: many processes, many employees, low degree of automation, typical labor-intensive operations. The quality management of post-process processes focuses on cultivating employees’ quality awareness. Through continuous training and learning of the “three no’s” principles of quality, employees know what to do and how to do it.
Not Acceptable: Any defective products will not be accepted, such as the wrong terminal wire diameter found at the sub-assembly station, wrong leaking holes found at the assembly station, inconsistent dimensions found at the appearance inspection station, etc. These all require awareness of mutual inspection;
Not manufactured: The operation process does not produce defects. Documents such as work instructions, key positions, and error-proofing must be clearly visible and employees must strictly follow the instructions. The “push-pull-push” inspection of plug-in terminals at the subassembly station is a typical example, which is inseparable from employees’ awareness of self-inspection;
Not passing on: After a defect is discovered, use red tape to clearly mark the suspicious location, isolate it, and do not pass it on to the next process. This is the special awareness of employees.

Crimping standards for wire harness terminals

On-site quality management of wiring harnesses is not the job of one department or one person. It requires the entire team to work together to continuously improve and do 3+3 on-site to take a big step forward in quality.